Abstract
This chapter considers the techniques necessary and required for the reprogramming of exogenous stem/progenitor cell populations towards a mammary epithelial cell fate. The protocols describe how to isolate cells from alternate mouse organs such as testicles of male mice and mix them with mammary cells to generate chimeric glands comprised of male and female epithelial cells that are fully competent. During the reformation of mammary stem cell niches by dispersed epithelial cells, in the context of the intact epithelium-free mammary stroma, non-mammary cells are sequestered and reprogrammed to perform mammary epithelial cell functions including those ascribed to mammary stem/progenitor cells. This therefore is a powerful technique for the redirection of cells from other organs/cancer cells to a normal mammary phenotype.